Epoxide-containing compositions

ABSTRACT

Curable compositions comprising: A. A MATERIAL FORMED BY HEATING A LIQUID MIXTURE OF A POLYCARBOXYLIC ACID ANHYDRIDE WITH AN EPOXIDE ALCOHOL FREE FROM CARBOXYL GROUPS, SO THAT AT LEAST 40 PERCENT OF THE ALCOHOLIC HYDROXYL GROUP CONTENT OF THE EPOXIDE ALCOHOL IS ESTERIFIED BY THE POLYCARBOXYLIC ACID ANHYDRIDE BUT NOT MORE THAN 25 PERCENT OF THE 1,2-EPOXIDE GROUP CONTENT OF THE EPOXIDE ALCOHOL HAS REACTED WITH THE POLYCARBOXYLIC ACID ANHYDRIDE, B. A BASE IN QUANTITY SUFFICIENT TO NEUTRALIZE AT LEAST SOME OF COMPONENT (A), AND, IF REQUIRED, C. A CURING AGENT FOR COMPONENT (A).

United States Patent [72] inventors Ian Geoffrey Hinton Whittlest'ord; Bernard Peter Stark, Stapletord, both 01 England [21] Appl. No. 702,532 [22] Filed Feb. 2, 1968 [45] Patented Dec. 14, 1971 [73] Assignee CIBA Limited Basel, Switzerland [32] Priority Feb. 13, 1967 [33] Great Britain [31 6,762/67 [54] EPOXIDE-CONTAINING COMPOSITIONS 16 Claims, No Drawings [52} US. Cl 260/29.3, 204/181, 260/18, 260/29.2, 260/29.4, 260/29.6, 260/47, 260/75, 260/78.4, 260/831, 260/834, 260/837 [51] Int. Cl ..C08g 51/24, C23b 13/00 [50] Field 01 Search 260/47 EP, 29.2 EP, 2 E1, 78.4 EP, 29.3

[56] References Cited UNITED STATES PATENTS 2,324,483 7/1943 Castan 260/47 2,698,308 12/1954 Crecelius 260/47 3,025,263 3/1962 Lee et a1. 260/47 3,052,650 9/1962 Wear et a1. 260/47 3,272,843 9/1966 Spatz et a1. 260/47 3,336,253 8/1967 Wong et a1..... 260/29.2 3,449,281 6/1969 Sullivan et a1. 260/29.2 2,752.269 6/1956 Condo et al. 260/2 2,970,983 2/1961 Newey 260/78.4 3,062,770 1 1/1962 Hirsch et a1. 260/29.2 3,355,401 11/1967 Tanner 260/29.2

OTHER REFERENCES Lee et a1. (text) Handbook," 1967, pages 5- 20 to 5- 25 are cited Primary Examiner-Julius Frome Assistant Examiner-Arthur H. Koeckert Attorneys-Harry Goldsmith, Joseph G. Kolodny and Bryant W. Brennan component (a), and, if required,

c. a curing agent for component (a).

EPOXEDE-CONTAINING COMPOSITIONS This invention relates to curable epoxide-containing compositions, and to hardened products obtained by pouring such compositions.

Electropainting, otherwise known as electrophoretic deposition, is fast becoming established as a means of coating metallic articles on a large scale, an example being the application of primer paints to car bodies. The article to be coated is suspended in a tank containing the paint which is a heatcurable, water-based, resinous colloidal electrolyte or resinous dispersion stabilize by a colloidal electrolyte. The article serves as one electrode, usually the anode, the tank, and/or one or more conductive articles of suitable dimensions suspended in the tank, being the other electrode. On passage of an electric current, the resin, and hardener and suspended pigment if present, are transported electrophoretically to the article to be coated, and are deposited thereon, primarily by discharge of the colloidal particles of the resin, although it is possible that dissolved ions of the metal article to be coated (the anode) also cause precipitation of the resinous particles. The water is forced away from the coating, probably by an electrolytic effect, although some at least of the water may be removed by electro-osmosis. The article is removed from the bath, rinsed and then baked to cure the coating.

It is known that epoxide resins, i.e. substances containing more than one 1,2-epoxide group per average molecule, can be cross linked by means of hardening agents, such as dicarboxylic acid anhydrides, which are at least difunctional with respect to the 1,2-epoxide groups, to form cured products of valuable technical properties and which may be used, inter alia, as surface coatings. Catalytic hardeners may also be used, such as monotertiary amines, which induce polymerization through the epoxide'groups. It is also known that substances containing only one 1,2-epoxide group per molecule can be cross linked by hardening agents which are at least trifunctional with respect to the 1,2-epoxide group.

While water-soluble and water-dispersible epoxides are known, these do not in general contain ionic groups which would permit their electrophoretic transfer and deposition upon metal substrates.

it has recently been proposed in British Pat. No. 1,080,172 to prepare a water-thinnable coating composition by reaction, to form a condensation polymer, between a glycidyl polyether of a dihydric phenol and acids consisting essentially of a. one or more monobasic aliphatic carboxylic acids derived from fats or oils or resin, and

b. one or more aliphatic or alicyclic polybasic acids containing in the molecule at least two carboxyl groups of which at least one is attached to a polymethylene group containing at least four carbon atoms, or the anhydride of such a fatty acid,

such that the individual proportions of (a) and of-(b) do not exceed the chemical equivalent of the glycidyl polyether, and adding to the polymer so obtained an amphipathic solvent and a neutralizing agent in an amount substantially sufficient to neutralize the acid groups in the polymer.

In this process, which is applied only to a certain class of polyepoxide, the glycidyl polyether reacts with the acids to give polymeric materials which are substantially free from epoxide groups. In a first stage, the epoxide ring is opened and a secondary alcoholic hydroxyl group is formed. As is shown later, the glycidyl polyether as originally employed may contain secondary alcoholic hydroxyl groups. On heating, reaction may occur between epoxide groups and the secondary alcoholic hydroxyl groups and also carboxyl-containing intermediates, produced by action of the dicarboxylic acid upon an epoxide group-containing material. In this manner, long-chain polymers are formed, but only at the expense of the epoxide groups: the products have few, if any, epoxide groups.

These polymers can be electrodeposited, and can be hardened or cured, i.e. converted into insoluble, cross linked structures, by heating. Curing apparently involves interreaction of polymeric molecules through their hydroxyl groups and also, since unsaturated acids or anhydrides are usually employed, by air-drying.

Van Westrenen, Weber, Smith and May (Proceedings 8th FATIPEC Congress, 1966, pp. 126-136) have recently described a similar process in which a polyglycidyl ether of a polyhydric phenol (which may, as will be shown later, contain secondary alcoholic hydroxyl groups) is heated with either an unsaturated fatty acid and then with maleic anhydride, or with a fatty acid (which need not be unsaturated) and then with phthalic anhydride. These products, too, may be dissolved or dispersed in water in the presence of a base and an amphipathic solvent, and coatings deposited from the solutions or dispersions by electrophoresis. The polymeric products are formed in a similar manner to those described in British Pat. No. 1,080,172, i.e. epoxide groups are consumed; they cure in a similar manner. These products likewise contain very few epoxide groups. I

It has now been found that epoxide alcohols may be reacted with polycarboxylic acid anhydrides to introduce, by esterification of the alcoholic hydroxyl groups, free carboxyl groups, without substantial destruction of the epoxide content, and that the-carboxyl group-containing products may be treated with bases to form hardenable, water-soluble or water-dispers ib le products.

The present invention accordingly provides curable compositions comprising:

a. a material formed by heating a liquid mixture of a polycarboxylic acid anhydride with. an epoxide alcohol free from carboxyl groups, so that at least 40 percent of the alcoholic hydroxyl group content of the epoxide alcohol is esterified by the polycarboxylic acid anhydride but not more than 25 percent of the 1,2-epoxide group content of the epoxide alcohol has reacted with the polycarboxylic acid anhydride,

b. a base in quantity sufficient to neutralize at least some of the free carboxyl groups of component (a),

and, if required,

c. a curing agent for component (a). Preferably, such curable compositions further-contain:

d. water, and v e. a substance rendering component (a), neutralized by (b), soluble in water. Products obtained by curing these curable compositions are within the scope of the invention.

Component (a) is suitably obtained by heating the epoxide alcohol with the polycarboxylic acid anhydride, preferably in the absence of any added solvent, at a temperature in the range 60 to 150 C., and preferably at to 130 C., for a period of at least 30 minutes, preferably from 1 to 3 hours. If desired however, a solvent that is inert to epoxide groups may be added, e.g. a ketonic solvent such as ethyl methyl ketone, isobutyl methyl ketone, sec.-butyl methyl ketone, phorone, isophorone, cyclohexanone or methylcyclohexanone. The anhydride is used in a quantity sufficient to supply from 0.4 up to a preferred maximum of 1.3 anhydride group equivalents per hydroxyl group equivalent of the epoxide alcohol.

The epoxide alcohol used to prepare component (a), unlike those the use of which is described in British Pat. No. 1,080,172 and in the FATIPEC article, need not be an esterified resin; in fact, it is preferred to employ an epoxide alpreferably contains no substituent groups, other than polycarboxylic acid anhydride groups, capable of reaction with the 1,2-epoxide groups or alcoholic hydroxyl groups of the epoxidealcohol. V 7

The alcoholic hydroxyl groups of the epoxide alcohol used to prepare component (a) are preferably primary or secondary.

The epoxide alcohol used may contain one 1,2-epoxide group per molecule, and may be, e.g., glycidol, or a compound of th formul CHEOH cmoH o 0 0H CH OH 0-011, 0-011, ofi tinon 0ft 0 o-t'm, 0 \.0OH

omen

cm-o cHomomoH o cm-o I Such monoepoxy cycloaliphatic alcohols may be obtained by epoxidation in known manner, e.g. with peracetic acid, of the corresponding monounsaturated cycloaliphatic alcohol. Epoxycycloaliphatic alcohols may also be obtained on epoxidation of cycloaliphatic compounds having two or more ethylenic double bonds but free from alcoholic hydroxyl groups, the hydroxyl groups being formed through solvolysis during epoxidation with a peracid.

Preferably, however, the epoxide alcohol contains, per average molecule, more than one 1,2-epoxide group, i.e. the epoxide alcohol is an alcoholic hydroxyl group-containing epoxide resin.

Those epoxy resins which are the most widely used commercially are those obtained by reaction of a compound having two or more phenolic hydroxyl groups with epichlorohydrin or glycerol dichlorohydrin either under alkaline conditions, or under acid conditions or in the presence of a catalyst followed by treatment with alkali. For example, the reaction of a dihydric phenol HO.Z.OH with epichlorohydrin in the presence of alkali may be represented asfollows: V 'v u This diglycidyl ether may, however, react with further Plateaus of tli'e diliydriphenol,this? glycerol,

and the terminal phenolic group so introduced may react with a further molecule of epichlorohydrin, and the product then undergo dehydrohalogenation as before. Alternatively, one molecule of the dihydric phenol may react with two molecules of the diglycidyl ether. The final product may be represented by the average formula o 2CHCH2(O' z-o omcnonormpoz-o omen- 311,

where p is a whole or fractional number. By suitable adjustment of the reaction conditions in a known manner, products may be obtained containing on average at least one alcoholic hydroxyl group per molecule,

Phenols containing two or more phenolic hydroxyl groups which may be so reacted to give hydroxyl-containing epoxy resins are, for example, resorcinol, catechol, hydroquinone, l ,4-dihydroxynaphthalene,- l ,S-dihydroxynaphthalene, bis( 4- hydroxyphenyl)methane, bis(4-hydroxyphenyl)-methylphenylmethane, bis(4-hydroxyphenyl)tolylmethanes, 4,4- dihydroxy-diphenyl, bis(4-hydroxyphenyl)sulphone, 2,2- bis(4-hydroxyphenyl)propane (Bisphenol A), and phenol-formaldehyde novolac resins.

Compounds containing two alcoholic hydroxyl groups may similarly be reacted, e.g. ethylene glycol and polyethylene glycols, propylene glycol and polypropylene glycols, propane- .1,3-diol, butane-1,4-diol, pentane-l,5-diol, hexane-1,6-diol,

and N-aryldialkanolamines such as N-phenyldiethanolamines, though with such compounds it is not so easy as with dihydric phenols to proceed beyond the product formed by reaction of one molecule of dihydric alcohol with two molecules of epichlorohydrin. Compounds containing three or more alcoholic hydroxyl groups may also be used, e.g.

3-hydroxymethylpentane-2,4-diol, hexane-2,4,6- triol, 1,l ,l-trimethylolpropane and pentaerythritol, when the epoxy alcohol may be produced by incomplete etherification with epichlorohydrin.

Apart from the foregoing compounds, which are polyglycidyl ethers, epoxy resins may be used in which at least one of the epoxide groups is directly attached to a cycloaliphatic nucleus, such as 3,4-epoxy-l-glycidoxymethyll-hydroxymethylcyclohexane.

Preferred epoxide alcohols are those of the formula:

wh eE Z denotes the rifiiiiinuia polyazelaic anhydride. Tetrahydrophthalic anhydride and 'hex ah yarophthalic anhydride are preferred.

The base (b) is preferably used in a quantity at least sufficient to neutralize the free carboxyl groups of component (a).

As examples of bases which may be used to neutralize the carboxyl groups there may be mentioned: ammonia, alkali metal hydroxides, and amines, including aminoalcohols such as ethanolamine and triethanolamine. Preferred bases are aqueous solutions of ammonia or sodium or potassium hydroxides. Neutralization should be effected in such a manner that the residual l,2-epoxide content of component (a) does not react with the base to such an extent that gelling or substantial cross linking of component (a) occurs. Conveniently, neutralization is carried out at about l5-25 C. The

tional. Examples of suitable such curing agents are pyromeldehyde resins, which may be phenol-formaldehyde resins.

etherii'ied as aforesaid, and

neutralized products typically have a useful life of some weeks 5 The compositions of the present invention may also contain at ordinary storage temperatures before gelation takes place. pigments, fillers, plasticizers dispersing agents and liquid As the substance (e), the amphipathic solvent, rendering monoor polyepoxides. the neutralized component (a) soluble in water, there may be The compositions may be used as adhesives, or as resins in used a volatile liquid aliphatic alcohol containing less than 10 the treatment of paper and textiles, and for fixing dyestuffs. a n t ms, Such a -P P L P P L ula 10 They are particularly suitable as surface coatings, and may be isobutanol or sec.-butanol, and it is preferred to employ a applied by brushing, roller-coating, dipping, spraying or elecvolatile liquid aliphatic monoether of an alkylene glycol or of trophoretic deposition. a dialkylene glycol, especially a monoether of ethylene glycol The following examples illustrate the invention. Unless with an alkanol containing from one to four carbon atoms: 2- otherwise indicated, epoxide contents were determined by n-butoxyethanol is particularly suitable. titration with hydrogen bromide in glacial acetic acid, (see in some cases, the neutralized modified resin may be cross Durbetaki, Analytical Chemistr 1956, 28, 2,000) and softenlinked, i.e. rendered insoluble and infusible, by the agency of ing points were determined by the ball and ring method. l'arts heat alone, through the ,reaction of the residual epoxide are by weight. 7 groups with the carboxyl ions. If desired, a catalyst for this EXAMPLES reaction, such as an alkali metal hydroxide, may be included. Th l d h f d In other cases, a cross linking agent may be necessary. Exam- 6 19 e resm w oye ter terme Epoxy ples of Such agents include polyamines such as resin A, was a poly lycidyl ether of Bisphenol A and had the ethylenediamine, diethylenetriamine, triethylerietetramine, aver: formula tetraethylenepentamine, propane-1,2-diamine, propane-1,3- 0 d N,N-d' th l th 1 d' N,N-d' th l- 1122211 3-diamine y e y we lamme bis(N-2- l i;:lro ir- 35:9?955495199H2930g2)'X'OCHzCQCH? yethyl)diethylenetriamine, isophoronediamine (l-amino-3- aminomethyl-3,5,S-trimethylcyclohexane), 1,6-diamino- X 2,2,4-and 2,4,4-trimethylhexanes, bis(4-aminocyclohexyl) CH; methane, 2,2-bis(4-aminocyclohexyl)propane, bis(4- aminophenyl)methane, aniline-formaldehyde resins, and poly- (aminoamides) such as those prepared from aliphatic WHEEL p ly and dimel'ized or tl'imel'iled Pnsatflrated y and r is approximately 3.4; it had an epoxide content of 2.0 acids. There may also be used polycarboxylic acids and their equivjkgi and a melting point range f 64 76 c portions f anhydridesi as P f acid; tetfahydrophthalic Epoxy resin A (each of 250 g.) were stirred and heated with f FQ P- iFi E a the anhydrides indicated in table i on an oil bath at [20 c. A adipic acid, ma eic acid, citric acid, pyrome itic acid, pht alic 0 Sample of each modified resin was dissolved in 10 of z gxi pq g g s g g fi i n-butoxyethanol, and distilled water was added until the resin hi' diid hz x a iij' dt giifhzl ic ainfii'drid iiia gc iii dto2:: 40 g n to eparate from solution. Sufficient aqueous ammonia domethylenetetrahydrophthalie anhydriiie and en- F fi gravity 9' was then added to dlssoiile the domethylenetetrahydrophthalic anhydride, and their mixpreclpnatc more dlsilued' wilter and addmons of tures, maleic anhydride, succinic anhydride, polysebacic anaqueolfs ammonfafoluuonnd dlsuned water i rehydride' polyazelaic hydride, pyromellitic dianhydridc and peateduntil the precipitated resin would no longer redissolve benzophenone-S,3',4,4'-tetra-carboxylic acid dianhydride. on addmg ammoma Solunonj I h The preferred curing agents are those capable of reacting both Table I the commons P w ma mg t c with I 2 epoxide groups and with alcoholic hydroxyl groups modified resins, the last two columns indicating the volume of in particular melaminbformaldehycle or urea formaldehyde distilled water that could be tolerated by the modified resin resins, which may be etherified with an aliphatic alcohol conf' the Volume P the aqueous ammonia mluuon requlred to taining from one to four carbon atoms, phenol-formaldehyde 8' {clear soluuon' I resins, and also acrylate resins containing free carboxyl 1! be Seen Illa! at least 30 P Ofthe epoxld? content groups of the resin was retained on reaction with the anhydride. That When component (a) has been prepared from a mono-l,2- reaction, i.e. esterification, had occurred, could be shown by epoxide alcohol, the curing agent should be at least trifuncdetermining the carboxyl group-content of the modified resin.

TABLE I Epoxide content of Anhydride modified resin Softening Volume of Volume of v E 111 cal P ri a of i tiiii ii distiuted aquem'ls V. 6 0 r0 0! 1011 mo 6 WB 81' ammonia Example Weight cglated on heating r tained resin tolerate required 0. Name (g.) OH-eontent (hrs.) Equiv./kg. (percent) C.) (m1.) (ml.) 150 1. 2 1 1.23 42 5.5 122 1% i 15:: i2 2 12 2 1 1. 0.8 2 1.2 250 a 76 0.6 1 1.4 10 5 .23 2-2 i z s2 3 f 2 25 0.' 2 254 117 s 2 200 o. 9 1 1.1 3 3 200 0.9 2 1.1 5 3 15.. do 200 0.9 3 1.1 12 2 16 Tetrahydrophthalie- 120 0. 9 1 1. 3 11 3 17.- do 120 0.9 2 1.1 100 2 18.- Methyltetrahydrophthalie 120 0.86 2 1, 2 10 2 19 Nonenylsuccinie 0.85 1 1. 2 8 2 20 do 160 0. 85 2 1. 2 35 2 Softening point determined by Kofler method.

Thus, a g. sample of the modified resin prepared as indicated in example 5.was dissolved in 25 ml. of acetone at room temperature and titrated against l-N aqueous sodium hydroxide solution with phenolphthalein as indicator. v

The epoxide resin-anhydride mixture before reaction contained 1.4 epoxide equivalents per kg, After heating for 1 hour, the epoxide content had decreased, as shown in table 1, to 1.3 equiv./kg. Since each epoxide group removed does so by reaction with an anhydride group with formation of one carboxyl group, this reduction causes a fall in the carboxyl group content of (1.4-1.3), i.e. 0.1 equivJkg. The original mixture had an anhydride content of 1.9 equiv./kg. Since one mole of anhydride reacts with two moles of sodium hydroxide, the corresponding carboxyl group content is 2X1.9, i.e. 3.8 equiv./kg. Hence, if the only reaction which had occurred was the opening of the epoxide ring with the anhydride, neutralization with sodium hydroxide would indicate a carboxyl content of (3.8-0.1), i.e. 3.7 equiv./kg. But the titration indicated a carboxyl group content of 2.5 equiv./kg. The content of esterified carboxyl groups is therefore (3.7-2.5), i.e. 1.2 equiv./kg. From this, it follows that the degree of conversion of the original anhydride groups into ester groups by reaction with the hydroxyl groups in the epoxide resin is 1.2/1.9X100 percent, i.e. 64 percent.

A sample of the modified resin, prepared as indicated in example 6, was similarly titrated. This resin was similar to that of example 5, but the reaction time was, as indicated in table 1, 2 hours. The decrease in epoxide content is (1.4-1.2), i.e. 0.2 equiv./kg. Hence, if opening of the epoxide ring by means of the anhydride was the only reaction occurring, the expected free carboxyl group content would be (3.8-0.2), i.e. 3.6 equiv./kg. The content, as determined by titration, is 1.9

equiv./kg., so the content of esterified carboxyl groups is 35 (3.6-1.9), i.e. 1.7 equiv./kg. The degree of conversion is therefore 1.7/1.9X100 percent, i.e. 90 percent. H V

Example 22:

Other samples of Modified resin 1 were diluted with an equal weight of 2-n-butoxyethanol, and stored at various temperatures. Changes in epoxide content and carboxylic acid content of the mixtures are shown in table 111.

Portions, each of 10 g. of Modified resin 11 (prepared by heating 100 g. of hexahydrophthalic anhydride with 250 g. of Epoxy resin A for 2 hours at 120 C.), were mixed with 10 g. of 2-n-butoxyethanol, and treated with a base as follows: Example 21: diluted with a mixture of 1.5 ml. aqueous ammonia (8.0. 0.88) and 78.5 ml. of distilled water;

adjusted to neutrality with 1 N-sodium hydroxide solution (using phenolphthalein as indicator) and diluted to 100 ml. with distilled water; Example 23: adjusted to neutrality with triethanolamine (using bromothymol blue as indicator) and diluted to 100 ml. with distilled water; Example 24: adjusted to neutrality with ethanolamine (using bromothymol blue as indicator) and diluted to 100 ml. with distilled water.

The useful lives of the diluted and neutralized modified resin solutions, i.e. the interval before gelation or precipitation occurred, are shown in table 1V.

EXAMPLES 21-24 V m I TABLE [V These examples illustrate the stability on storage at various temperatures of the neutralized modified resins. Exampl s: a

The modified resin used, (Modified resin 1"), was 20 40 60 prepared by heating 100 g. of hexahydrophthalic anhydride with 250 g. of Epoxy resin B for 2 hours. (Epoxy resin B was days days 5 22 14 days 14 days 8 days similar to Epoxy resin A but had a slightly higher epoxide con- 23 days 4 days day tent). Samples of Modified resin 1 were stored at various tem- 24 10 days 4 days i day peratures and the change in epoxide content and softening point were noted. The results obtained are shown in table 11.

EXA LE TABLE I1 P 25 A mixture of Epoxy resin A 1,000 g.) and Storage m comm seaming poi, tetrahydrophthalic anhydride (400 g., 0.75 equiv. calculated Conditions (equivjkg) (Koflcr) on the hydroxyl content) was heated for 2 hours at 130 C., followed by heating at 120 C. for various lengths of time. Initial value 1.4 70C. Samples, each of 10 g., of the products were mixed with 10 g. C-/14 y of 2-n-butoxyethanol, diluted to 10 percent solids content 40C. days 1.4 76C. t f a S G 0 88 l 5 b 0 days H 92C 1 a mix ure 0 aqueous ammonia parts y (3J2 0] We volume) and distilled water (78.5 parts by volume), and kept 100 c./4 days 1.4 115 c. 60 at 40 C.

The results obtained are shown in table V.

TABLE V Epoxlde Carboxyl Softening Stability of content content point, Initial appearance solution at (equiv./kg.) (equ1v./kg.) Kofler (C.) 01 solution 40 0. (days) After 2 hours/130 C 1. 3 1. 9 81' htl l t. 0 Plus 1 hour/120 C 1. 1 1.8 79 Cigar ffi i ff i l n. :10 Plus 2 hours/120 O-.. 1.0 1.8 do 10 Plus 3 hours/120 C Resin gelled EXAMPLE 26 Epoxy resin A (1 kg.) and hexahydrophthalic anhydride (400 g., 0.75 equiv. calculated on the hydroxyl content) were mixed at 130 C. and heated with stirring at this temperature 5 for 2 hours. To the product was added 2-n-butoxyethanol (1,400 g.,) and the solution (Modified resin [11) was cooled to 20 c.

Samples of Modified resin 111 were diluted with an equal weight of either 2.5 percent aqueous ammonia solution or 1 N-aqueous sodium hydroxide solution, and stored at 20 C. The changes in epoxide content of the products are shown in table Vl. It will be seen that the epoxide content decreased quite slowly. 1

; 15 TABLE VI Time elapsed Epoxide content (equiv.kg.) after preparing solution Aqueous ammonia Aqueous sodium hydroxide l min. 0.32 0.29 1 hour 0.32 0.29 2 hours 0.31

3 hours 0.30

4 hours 0.29 24 hours 0.11 0.26 48 hours 0.18

A mixture of 100 parts of Modified resin 11!, 110 parts of ammonia solution (prepared by diluting one volume of ammonia solution, 8.0.0.88, with nine volumes of distilled water) and 100 parts of distilled water had not gelled after storing at room temperature for 5 months.

EXAMPLE 27 The epoxyalcohol used had the formula EXAMPLE 28 A mixture of 20 g. of Modified resin Ill and 0.5 g. of 25 percent aqueous trimethylamine was spread on aluminum sheets and baked for 1 hour at 100 C. Hard, flexible films, resistant to acetone, were obtained.

A 20 g. sample of Modified resin [11 was mixed with 4 g. of 25 percent aqueous trimethylamine and 0.2 to 1 g. of triethylenetetramine. This mixture could be diluted with up to 60 ml. of water without precipitating the modified resin. The undiluted mixture was applied to aluminum sheets; on curing at 20 C. for 2 weeks, hard, clear coatings, resistant to acetone, were obtained.

For purposes of comparison, two resins were prepared, the first (Esterified resin 1V") following the method described in British Pat. No. 1,080,172, and the second, (Esterified resin V" as described b my .Wsstrqnsastgat eirfifl fEC thcfl ms occurred.

Congress paper referred to above. Esterified resin lV Epoxy resin A (950 parts), linseed oil fatty acids (1,050 parts) and sodium carbonate, decahydrate (0.15 part) were heated at 220 C. in an atmosphere of nitrogen, xylene being dripped in to remove the waterformed as an azeotrope. When the acid value dropped to just below 10 mg. KOH per gram, the mixture was cooled to not more than 140 C., Admerginate acid LP" (433 parts) was added, and heating was continued for 6 hours at 140 C. The acid value dropped to 53 mg. KOH per gram after 2 hours, and remained at that value during the rest of the period of heating.

Admerginate acid LP." is supplied by J. Bibby and Sons, Limited, Liverpool, England, and is believed to have the formula where R denotes a pentyl or hexylgroup and R denotes a polymethylene chain having eight or seven carbon atoms.

seed oil fatty acids (142 parts) containing 0.08 part of sodium carbonate decahydrate heated to C. in an atmosphere of nitrogen. The temperature was raised to 160 C. and xylene was added as in the preparation of Esterified resin IV. The temperature was next increasedto 220 C. and held there until the acid value was 8-10. Then the mixture was cooled to C., and the calculated amount of phthalic anhydride required to achieve a final acid value of 50 mg. KOH per kg., i.e. 42

.parts, was added. Heating was continued at C. for 6 hours. The epoxide content of the product, as determined by .lays method, was only 0.0 23 equiv.(kg V I A film comprising 100 parts of Modified resin 111 and 2.75 parts of triethylenetetramine was applied to glass, and left at r emle rzsaa yrsf rj 9x Tbat at ns h k Place was shown by the resistance of the film in the acetone rub test. Similar results were obtained if the composition were diluted with 190 parts of water plus 10 parts of aqueous ammonia, 5.6. 0.88, before application to glass.

Films of mixtures comprising 100 parts of Esterified resin IV or Esterified resin V and 2.75 parts by weight of triethylenetetramine were likewise applied to glass and kept at room temperature. Despite prolonged storage, no curing of That the mixture of Modified resin Ill and Maine cured at room temperature, while mixtures of an amine and Esterified resins 1V and V did not, demonstrates unequivocally that only the composition of the present invention contained sufficient epoxide groups to cure through thesegroups.

A further 20 g. sample of Modified resin 111 was mixed with 2 ml. of aqueous ammonia solution (S.G. 0.88) and 3 g. of a .methoxymethylmelamine resin (Melamine resin Vl) conacetone for 1 hour. incorporation of toluene-p-sulphonic acid d A m 40 rte resin 8- (O.2 g.) in the mlxture dld not affect the water solubility but aqueous ammcniusa 0.88) 3 accelerated the rate of cure and improved the hardness of the distilled w i 157 ml. coatin 5. Solution B E 5 Acrylate resin Vlll 403. Two mixtures were prepared, containing lOO parts of hmmyflhanoi 10 Modified resin ill, lOO parts of aqueous ammonia solution i ill w r ml (prepared by diluting one volume of aqueous ammonia solusolution A I00 3. tion, SC. 0.88, w1th nme volumes of distilled water), 18 or 20 salmon B 100 8,

parts of a 70 percent w/w aqueous solution of a methoxu l ymelhylmelamme r651" Melamine Yes"! Y" containing 0 Properties of the coatings obtained on the anodes are shown approximately 4.4 methoxymethyl groups and approximately i t ble Vlll, 1.6 free methylol groups per molecule, and 100 parts of TABLE vm distilled water. The mixtures were clear when first prepared, but turned cloudy after five minutes. This cloudiness was removed by adding 10 parts of the diluted aqueous ammonia Elcctwdeposilion Rinsed mating Rinsed q s solution. from before stoving after stoving These mixtures were sprayed onto aluminum panels 0.315

mm. thick, and the coated panels were stored at 150 C. for 30 A i g gr gx minutes (see British Ministry of Defense specification DEF So'mionB somslicky bzime'solublc 1053). The hardened films had good resistance to acetone, in e w e and were flexible, i.e. the panels could be bent around a man 501mb" C Opaque. soft gfglctzilsasllalghfly drel of diameter 3.2 mm. without the film cracking. mm y Pigmented films could be prepared from these mixtures by incorporating 50 percent by weight of titanium dioxide (such EXAMPLE 3] as that available from British Titan Products Co. Ltd. under the designation Tioxide RCR3"). The optimum curing The solutions used were: conditions for such pigmented films were 140 C. for 20 mmutes' Solution D Modified resin Ill I00 parts dilute aqueous ammonia, I00 parts EXAMPLE 29 (one volume aqueous amr'nonia, 8.6.

I 0.88 to nine volumes distilled water A water-soluble acrylate resin, hereinafter known as Acry- Melamine resin v11 18 pans late resin Vlll," was prepared by heating 140 g. of acrylic acid, 5 l r 900 0 ll lOl'l 360 g. butyl acrylate, 500 g. styrene, 1 kg. of n-butanol and 15 Escrmed min w '00 Pam g. of dodecyl mercaptan at l20 C. for 10 hours under reflux distilled water 900 parts while cumene hydroperoxide (30 g.) was added portionwise, l-diflhylimimelhflml ztg' a s cooling the mixture to 25 C. and adding 100 ml. of aqueous a i ammonia (SC. 0.88). solution F I V V am Modified resin ill and Acrylate resin Vlll were mlxed in the F v P d t d b low s read on aluminum sheets and mulled mm 900 Ram Proporuons m e e p 2diethylaminoethanol suffiuent to cured at l90 C. Table Vll shows the properties of the cured bring pH to films. 5.5-9.0

TAB LE VII Parts by weight:

Modified rosin III 100 80 75 67 33 25 20 0 Acrylate resin VIII. 0 20 25 33 50 67 Curing time:

0.5 hour Flexible, Flexible, Flexible, Flexible, Flexible, Brittle, Brittle, Brittle, Brittle,

acetone softened softened softened softened softened softened acetone acetone soluble by aceby aoeby eceby aceby aeeby acesoluble soluble.

tone tone tone tone tone tone 1 hour d0 do -do do -do Flexible, Flexible, Flexible, Do.

softened softened acetone by aceby ace- 1 soluble --tone tone 2 hours do do Flexible, Flexible, Flexible, do do do Do.

slightly slightly slightly softened softened softened by eceby aoeby acetone tone tone EXAMPLE 30 65 In preparing solutions E and F, the distilled water was added Two electrodes, each anabraded and degreased steel plate m Portions, with alternating additions of l0 cm.x5 cm., were suspended 2.5 cm. apart in the solutions diethylaminoethanol in quantities Sumciem to Prevent described below and subjected to a potential difference of 14 pfq p l of l i quantity of amine the last volts (direct current). The coated anodes were removed, dltlo" being sufficlem to bring the P the Value Show rinsed with distilled water, and stored at C. for 1 hour. 70 Coatings approximately 0.02 mm. thick were applied elec- The solutions used were: trophoretically to steel or aluminum plates at 60 volts, the

time of deposition being 10 seconds. Unless stated otherwise,

urea-formaldehyde resin, melamine-formaldehyde resin the coatings were cured at 150 C. for 30 minutes. Results obetherified with an aliphatic alcohol containing one to four tained in varioustests are shown in table IX. carbon atoms, phenolformaldehyde resin, and acrylate resin containing free carboxyl groups. TABLE IX 5 3. A composition as claimed in claim 1 wherein the epoxide alcohol employed as starting material for preparing com- Coating from" ponent (a) is free from esterified carboxyl groups.

Test Solution D Solution E Solution F 4. A composition as claimed in claim 1 wherein component Colour: (a) is formed by heating the epoxide alcohol with the dicar- Alternormal curing Good Fair Fair. boxylic acid anhydride in the absence of any added solvent gi a g figsf gi Poor Poor and at a temperature in the range 60 to l50 C.

ance to ovcrbaklng. 7. A composition as claimed in claim 6, wherein component gag gggfi fig igggfigg satlsmclorysoftenei (a) is formed by heating the epoxide alcohol and the dicarbox- 6 days): ylic acid anhydride at a temperature in the range 80 to 130 Ketchup do Satlslactory Satisfactory. C Mustard do ..do Do.

' Slight wi Slight Stain, 6. A composition as claimed in claim 1, wherein component f g g g (a) is formed by heating together the epoxide alcohol and "$510556?" No 1 r dicarboxylic acid anhydride for at least 30 minutes.

Chemical resistance glossj E1055- 7. A composition as claimed in claim 6, wherein component Boiling water8 hours Satisfactory. Satisfactory. Failed after is formed y heating together the epoxidc alcohol and 20% sodium hydroxide do do H g gg f dicarboxylic acid anhydride forfrom l to 3 hours Solution-4 days, 8. A composition as claimed in claim 1, wherein the epoxide gl g i gfi f i g g ffi alcohol used for the preparation of component (a) has a 1,2-

volumes g epoxide content of at least l.0 equivalent per kilogram. hours P001 9. A composition as claimed in claim 1, wherein the epoxide 5 days .do do Failed.

50% Sulphuric mm. alcohol used for the preparation of component (a) contains no 24 hours Severe substituent grou s, apart from 1,2-epoxide groups and al- 5 days Fair Fair g g cohohc hydroxy groups, capable of reaction with the dicar- 10% acetic acid boxylic acid anhydride.

g ggg i i 332 3 10. A composition as claimed in claim 1, wherein the epox- Industrial iiioiihiiid Satisft'dfif Satii66 Satisfactory. de alcohol used for the preparation of component (a) cong g gfi ig s "do D0 tains, per average molecule, more than one 1,2-epoxide Humi ity test5 days d0 Sliggisticgr- Do. g p I h the dicar v 11. A composltion as claimed in claim 1, w erem Salt Spray test 5 days Satisfactory" fi fi?" boxylic acid anhydride used for the preparation of component (a) contains no substituent'groups, other than dicarboxylic Brmsh Ministry of D9? {1531s EL... W* acid anhydride groups, capable of reaction with 1,2-epoxide groups or alcoholic hydroxyl groups of the epoxide alcohol. The superior properties of the coating deposited from a 12. A composition as claimed in claim 1, wherein the alcomposition of the present invention, particularly in chemical 40 coholic hydroxyl groups of the epoxide alcohol used for the and stain resistance, and also tolerance to over-baking, are preparation of component (a) are members selected from the readily apparent. group consisting of primary alcoholic hydroxyl groups and We claim: secondary alcoholic hydroxyl groups. I. A curable composition of matter suitable for coating arti- 13. A composition as claimed in claim 1, wherein the epoxcles by electrophoretic deposition comprising: 4 5 ide alcohol used for the preparation of component (a) is of the a. a reaction product formed by heating a liquid mixture of a formula dicarboxylic acid anhydride with an epoxide alcohol free from carboxyl groups, the anhydride being used in a quantity sufficient to supply from 0.4 to 1.3 anhydride CIIz-'CI'ICIIZ(O.Z.OCII CIIOHCIIZ)qO-Z.oCH2CHg-CH2 group equivalents per hydroxyl group equivalent of the epoxide alcohol, so that at least 40 percent of the alcoholwhere Z denotes the group of formula ic hydroxyl group content of the epoxide alcohol is esterified by the dicarboxylic acid anhydride but not 0 more than 25 percent of the 1,2-epoxide group content of l the epoxide alcohol has reacted with the dicarboxylic acid anhydride, a and, b. a base in quantity at least sufficient to neutralize the free carboxyl groups of component (a). and q is a number having a value of at least one but not more 2. A curable composition of matter suitable for coating artithan 10. cles by electrophoretic deposition comprising: 14. A composition as claimed in claim 1, wherein the dicara. a reaction product formed by heating a liquid mixture of a boxylic acid anhydride used for the preparation of component dicarboxylic acid anhydride with an epoxide alcohol free (a) is a member selected from the group consisting of from carboxyl groups, the anhydride being used in a tetrahydrophthalic anhydride and hexahydrophthalic anquantity sufficient to supply from 0.4 to 1.3 anhydride hydride. group equivalents per hydroxyl group equivalent of the 15. A composition as claimed in claim 1, wherein the base epoxide alcohol, so that at least 40 percent of the alcohol- (b) is an aqueous solution of a member selected from the ic hydroxyl group content of the epoxide alcohol is group consisting of ammonia, sodium hydroxide and potassiesterified by the dicarboxylic acid anhydride but not um hydroxide. more than 25 percent of the 1,2-epoxide group -epoxide 16. A composition as claimed in claim 2, wherein the curing of the epoxide alcohol has reacted with the dicarboxylic gen i a m m elected fr m he gr p consisting of acid anhydride; melamine-formaldehyde resin, urea-formaldehyde resin, b. a base in quantity at least sufficient to neutralize the free melamine-formaldehyderesin etherified with an aliphatic alcarboxyl groups of component, and cohol containing one to four carbon atoms, urea-formalc. a curing agent for component (a), which i a member dehyde resin etherified with an aliphatic alcohol containing selected from the group consisting of polycarboxylic acid, one to four carbon atoms, phenol-formaldehyde resin and polycarboxylic anhydride, melamine-fo lg l ge i n acrylate resin containing free carboxyl groups.

CERTIFICATE OF fiORREUiIN Patent No. 3,627,720 Dated December 1 4-, 1971 Inventofls) Hinton 9t 81 It is certified that error appears in the above-identified patent I and that said Letters Patent are hereby corrected as shown below:

Column 13, line 69, delete "-epoxide"(seoond occurrence); line 73, before "and" insert (a) Column 14, line 12, "7" should be 5 same line, "6" should be "4 line ,9 should read:

CH2 CHCH2( 0. z OCH2CHOHCH2) 0. 2 OCH2CH-- CH2 Column 13, line 69,. after "group" insert content Signed and sealed this 18th day of July 1972.

(SEAL) Attest:

EDWARD M.FLETCHER, JR. ROBERT GOT'I'SCHALK Commissioner of Patents Attesting Officer 

2. A curable composition of matter suitable for coating articles by electrophoretic deposition comprising: a. a reaction product formed by heating a liquid mixture of a dicarboxylic acid anhydride with an epoxide alcohol free from carboxyl groups, the anhydride being used in a quantity sufficient to supply from 0.4 to 1.3 anhydride group equivalents per hydroxyl group equivalent of the epoxide alcohol, so that at least 40 percent of the alcoholic hydroxyl group content of the epoxide alcohol is esterified by the dicarboxylic acid anhydride but not more than 25 percent of the 1,2-epoxide group content of the epoxide alcohol has reacted with the dicarboxylic acid anhydride; b. a base in quantity at least sufficient to neutralize the free carboxyl groups of component, and c. a curing agent for component (a), which is a member selected from the group consisting of polycarboxylic acid, polycarboxylic anhydride, melamine-formaldehyde resin, urea-formaldehyde resin, melamine-formaldehyde resin etherified with an aliphatic alcohol containing one to four carbon atoms, phenolformaldehyde resin, and acrylate resin containing free carboxyl groups.
 3. A composition as claimed in claim 1 wherein the epoxide alcohol employed as starting material for preparing component (a) is free from esterified carboxyl groups.
 4. A composition as claimed in claim 1 wherein component (a) is formed by heating the epoxide alcohol with the dicarboxylic acid anhydride in the absence of any added solvent and at a temperature in the range 60* to 150* C.
 6. A composition as claimed in claim 1, wherein component (a) is formed by heating together the epoxide alcohol and dicarboxylic acid anhydride for at least 30 minutes.
 7. A composition as claimed in claim 6, wherein component (a) is formed by heating together the epoxide alcohol and dicarboxylic acid anhydride for from 1 to 3 hours.
 7. A composition as claimed in claim 6, wherein component (a) is formed by heating the epoxide alcohol and the dicarboxylic acid anhydride at a temperature in the range 80* to 130* C.
 8. A composition as claimed in claim 1, wherein the epoxide alcohol used for the preparation of component (a) has a 1,2-epoxide content of at least 1.0 equivalent per kilogram.
 9. A composition as claimed in claim 1, wherein the epoxide alcohol used for the preparation of component (a) contains no substituent groups, apart from 1,2-epoxide groups and alcoholic hydroxyl groups, capable of reaction with the dicarboxylic acid anhydride.
 10. A composition as claimed in claim 1, wherein the epoxide alcohol used for the preparation of component (a) contains, per average molecule, more than one 1,2-epoxide group.
 11. A composition as claimed in claim 1, wherein the dicarboxylic acid anhydride used for the preparation of component (a) contains no substituent groups, other than dicarboxylic acid anhydride groups, capable of reaction with 1,2-epoxide groups or alcoholic hydroxyl groups of the epoxide alcohol.
 12. A composition as claimed in claim 1, wherein the alcoholic hydroxyl groups of the epoxide alcohol used for the preparation of component (a) are members selected from the group consisting of primary alcoholic hydroxyl groups and secondary alcoholic hydroxyl groups.
 13. A composition as claimed in claim 1, wherein the epoxide alcohol used for the preparation of component (a) is of the formula where Z denotes The group of formula and q is a number having a value of at least one but not more than
 10. 14. A composition as claimed in claim 1, wherein the dicarboxylic acid anhydride used for the preparation of component (a) is a member selected from the group consisting of tetrahydrophthalic anhydride and hexahydrophthalic anhydride.
 15. A composition as claimed in claim 1, wherein the base (b) is an aqueous solution of a member selected from the group consisting of ammonia, sodium hydroxide and potassium hydroxide.
 16. A composition as claimed in claim 2, wherein the curing agent (c) is a member selected from the group consisting of melamine-formaldehyde resin, urea-formaldehyde resin, melamine-formaldehyde resin etherified with an aliphatic alcohol containing one to four carbon atoms, urea-formaldehyde resin etherified with an aliphatic alcohol containing one to four carbon atoms, phenol-formaldehyde resin and acrylate resin containing free carboxyl groups. 